The people who do not hesitate to tell from which sect they belong should think twice before associating themselves with sects before Allah does not like it as he mentioned in Quran. Most of the people does not even knows the complete beliefs of some particular sect but they still argue with other people to prove themselves right. Please view some of the Ayah's related to sects in Quran.
23:53 - But people have cut off their affair (of unity), between them, into sects: each party rejoices in that which is with itself.
42:14 - And they became divided only after Knowledge reached them,- through selfish envy as between themselves. Had it not been for a Word that went forth before from thy Lord, (tending) to a Term appointed, the matter would have been settled between them: But truly those who have inherited the Book after them are in suspicious (disquieting) doubt concerning it.
45:28 - And thou wilt see every sect bowing the knee: Every sect will be called to its Record: "This Day shall ye be recompensed for all that ye did!
19:37 - But the sects differ among themselves: and woe to the unbelievers because of the (coming) Judgment of a Momentous Day
16:159 - As for those who divide their religion and break up into sects, thou hast no part in them in the least: their affair is with Allah: He will in the end tell them the truth of all that they did
13:36 - Those to whom We have given the Book rejoice at what hath been revealed unto thee: but there are among the clans those who reject a part thereof. Say: "I am commanded to worship Allah, and not to join partners with Him. Unto Him do I call, and unto Him is my return."
